This protocol investigates the use of the radiosensitizer IUdR and radiation therapy for soft tissue sarcomas of the head and neck, trunk, retroperitoneum, and extremity. Patients receive one week of IUdR (1,600 mg/m(2)/d) by IV infusion. This is followed by a week of external beam radiation (250-300c Gy/d) in 2 doses is repeated 2 more times whereupon resection is carried out and 2 more cycles are delivered post-operatively. Unresectable tumors receive all 5 cycles are delivered post-operatively. Unresectable tumors receive all 5 cycles and are re-evaluated for resectability.